Integrally Bladed Rotors (IBR's), also commonly known as “bladed discs”are important parts of gas turbine engines. Manufacturing IBR's is a challenging task due to the complex geometry of airfoil surfaces. Existing methods of manufacturing IBR airfoils include flank milling, point milling, etc. In a flank milling process, the periphery of an end mill, typically a tapered ball end mill, generates the desired airfoil surface geometry through one or more passes of the cutter. The tool used in a point milling process is usually a tapered ball end style milling cutter. In both cases (flank and point milling) the tools are small enough such that the entire diameter of the tool can fit between the airfoils of the IBR. These milling cutters have cutting teeth and flutes which either extend straight down the cutter, or can extend around the cutter in a helical direction. The helical blade arrangement is often preferred because when using that type of cutter, a portion of the tooth is always in contact with the work piece and the teeth tend to slice off cuttings rather than chip them away. The number of flutes and cutting teeth is conventionally limited to, for example 3 to 6, depending on the diameter of the milling cutters, in order to ensure a desired dimension of the flutes in particular, for accommodating the chips removed from parts during operation. However, such conventional milling cutters used for semi-finishing and finishing operations may suffer disadvantages of, for example, low productivity, poor airfoil surface finish, limited tool life, irrational us of expensive tool material, etc.
Accordingly, there is a need for optimization of milling cutters for semi-finishing and finishing machining of IBR airfoils.